Machine for forming random fiber webs

ABSTRACT

A web composed of long and short fibers can be produced on this machine. Two separate air ducts convey the two types of fibers to two rotating condensers on which the respective fibers are laid down forming fiber mats. The fibers are combed from the two mats by two rotating lickerins and are doffed from the lickerins by two separate air streams flowing past the lickerins and by the centrifugal forces created by the high speed rotation of the lickerins. They are carried by the air streams into a mixing and expansion chamber in which the fibers blend and intermingle. Pivotal vanes disposed above or in the air streams and a divider plate adjustable into the mixing and expansion chamber control the direction and flow of the air streams to control the positions and relative amounts of the long and short fibers in the random fiber web formed in the machine.

United States Patent Wood [ Oct. 28, 1975 Primary ExaminerDorsey Newton[5 7] ABSTRACT A web composed of long and short fibers can be producedon this machine. Two separate air ducts convey the two types of fibersto two rotating condensers on which the respective fibers are laid downforming fiber mats. The fibers are combed from the two mats by tworotating lickerins and are doffed from the lickerins by two separate airstreams flowing past the lickerins and by the centrifugal forces createdby the high speed rotation of the lickerins. They are carried by the airstreams into a mixing and expansion chamber in which the fibers blendand intermingle. Pivotal vanes disposed above or in the air streams anda divider plate adjustable into the mixing and expansion chamber controlthe direction and flow of the air streams to control the positions andrelative amounts of the long and short fibers in the random fiber webformed in the machine.

U.S. Patent Oct.28, 1975 Sheet10f3 3,914,822

FIG.

U.S. Patent 0a. 28, 1975 Sheet 2 of 3 3,914,822

US. Patent Oct. 28, 1975 Sheet3 of3 3,914,822

MACHINE FOR FORMING RANDOM FIBER WEBS The present invention relates to amethod and apparatus for producing non-woven textile articles, that is,textile articles produced without spinning, weaving or knittingoperations. In a more specific aspect, the invention relates toorganized machines of the general type disclosed in the Langdon U.S.Pat. No. 3,512,218, issued May 19, 1970 and in the Wood U.S. Pat. No.3,535,187, issued Oct. 20, 1970.

With the machines of the prior patents mentioned difficulties have beenexperienced in getting a uniform blend of fibers of different lengths ina random fiber web. Another disadvantage encountered sometimes withthese prior machines is that of securing desired ratios and desiredvarieties of fiber distribution in a web.

One object of the present invention is to provide a machine capable offorming random fiber webs from a blend of long and short fibers. Thelong fibers may be of natural or synthetic origin and of textile length.The short fibers may be paper making fibers, such as produced from woodpulp, or cotton linters, or the like.

Another object of the invention is to provide a machine of the characterdescribed in which the proportion of short fibers to long fibers mayreadily be adjusted as required by the type of random fiber web which itis desired to produce.

. Another object of the invention is to provide a machine of thecharacter described which can produce selectively webs that havedifferent fiber distributions, for instance, webs that have outer layersmade up each of two different fibers and an intermediate layer that is ahomogeneous blend of the two fibers, or webs in which the fibers of onetype predominate at one side of the web and fibers of another typepredominate at the other face of the web and where the two differenttypes of fibers intermingle at the center of the web, or a web made oftwo separate layers of different fibers that are only intermingled atthe region of their interface.

Another object of the invention is to provide a machine of the characterdescribed which will produce a random fiber web having substantiallyuniform strength lengthwise and crosswise and depthwise thereof.

Another object of the invention is to provide a machine of the characterdescribed which will operate more efficiently and at higher speed thanmachines of this type previously constructed.

Still another object of the invention is to provide a machine which willproduce improved, non-woven webs. To this end, a further object of theinvention is to provide a machine of the character described which willeliminate the formation of objectionable lumps of fibers in the finishednon-woven web.

A still further object of the invention is to provide a machine whichwill produce non-woven webs stronger than present such webs.

Other objects of the invention will be apparent hereinafter from thespecification and from the recital of the appended claims, particularlywhen read in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a somewhat diagrammatic, fragmentary sectional view in avertical plane through web forming apparatus made according to oneembodiment of this invention;

FIG. 2 is a similar view showing a modification of the machine; and

FIG. 3 is a similar view illustrating fragmentarily a still furtherembodiment of the invention.

The machine of this application is quite similar generally to themachine of the Langdon U.S. Pat. No. 3,512,218. Air-borne fibers ofdifferent characteristics, respectively, may be delivered to the machinethrough chutes 10 and 12, which in turn deliver them into trumpets 14and 16, which form parts of air bridge systems that convey the fibersfrom the chutes 10, 12 to rotary feed condensers 1 8 and 20.

The condensers may be of conventional construction and comprise rotaryscreens 22, 24 which revolve about fixed suction tubes 26, 28,respectively. The outer walls of the trumpets converge around thecondensers toward the periphery of the condensers so as gradually tocompress the fiber mats formed on the condensers by the fibers depositedthereon. Doffing rolls 30 and 32, respectively, which are disposed incontiguity to the condenser screens, doff the fiber mats, which are laiddown on the condenser screens onto feed plates 34 and 36, respectively.These feed plates are extensions of the plates that bound one side ofeach of the trumpets l4 and 16.

The mats are picked up by feed rolls 38 and 40, which feed the mats overthe nose bars 42, 44 that are secured to the feed plates. The feed rollsfeed these mats into the rotating'lickerins 46 and 48, respectively. Thelickerins are of standard construction as are the feed plates andfeedrolls.

The lickerins have peripheral teeth which comb fibers from the mats asthe mats are fed into the lickerins and as the lickerins revolve. Thelickerins are driven at high speed according to conventional practice;and the fibers are doffed from the teeth of the lickerins by centrifugalforce and by air streams flowing over the teeth of the lickerins.

The air streams for doffing the fibers from the lickerins are suppliedthrough an air inlet tube 50 which may be fed by a pressure fan or fans.A restrictive slot 52 in this duct 50 equalizes the widthwise flow intothe plenum or air chamber 54 through which the duct 50 extends. Thisplenum may be of generally rectangular cross section, as illustrated inU.S. Pat. No. 3,512,218, and has ports in its bottom through which theair flows into a common air balancing chamber 56.

Mounted in this chamber 56 are two pivoted deflectors 58, 60 which aredisposed at opposite sides, respectively, of an intermediate fixeddeflector 62.

The opposite sides of this balancing chamber 56 are bounded by the feedplates 34, 36, which in their upper portions have downwardly generallyconverging surfaces 61, 63 and in their lower portions have downwardlyconverging sidewalls 64, 66.

Mounted within the air chamber 56 is an air divider 68, which is ofgenerally triangular shape in cross section with its apex at its top.Joumaled on eccentric bushings in the bottom of the divider at oppositesides thereof, respectively, are rotary sabers and 72; and reciprocablymounted within the divider to be adjustable vertically between the twosabers is a plate 74, which like the divider 68, extends across the fullwidth of the chamber 56. Adjustment of this plate is effected byrotation of a pinion 76 which engages a rack 78 formed on the plate. Twodifferent positions of the plate are shown in full and in dotted lines,respectively, in FIG. 1.

Air flow from chamber 56 past the lickerins serves, in combination withthe centrifugal force produced by the high speed rotation of thelickerins, to doff the fibers from the lickerins, and carry the fibersdownward into an aerodynamic fiber mixing and expansion chamber 80.

The air flowing through the air balancing chamber 56 splits at the apexof divider 68, passes through the passageways between the lickerins andthe sides of the divider 68, and serves in conjunction with thecentrifugal force produced by the high speed rotation of the lickerins,to doff the fibers from the lickerins. The air velocity is a maximumnormal to the lickerins. Doffing blades 77, 79 juxtaposed to thelickerins aid in the doffing action by preventing fibers being carriedaround the lickerins in the bound layers of air.

The doffed fibers are carried by the two air streams into the fibermixing and expansion chamber 80 and are deposited on an endless screencondenser 82, that may be made on Fourdrinier screening and that travelsacross the mouth of chamber 80 over two rolls 84 and 86, which aremounted on two rotary shafts 88 and 90, respectively. The roll 86 may bedriven from a motor 92 through pulleys 94 and 96, respectively, and thebelt 98.

Mounted within the screen 82 is a negative air pressure chamber orsuction box 100, which is connected by air ducts 102 and 104 to airducts 106 and 108 which deliver the air to suction fans (not shown) thatin turn deliver the air to opposite ends of the air inlet tube 50. Theconstruction is similar to that shown in U.S. Pat. No. 3,521,218.

The adjustable, eccentrically-mounted rolls 70 and 72 regulate thevelocity of the air via a venturi section at each side of the chamber 56and are adjustable independently of each other selectively to throttlethe air and fibers passing out of the lower ends of the passagewaysformed on opposite sides of divider 68. Hence the flow and velocity ofair is adjustable to the necessary proportions called for by thedifferent types and quantity of fibers being processed through themachine. Two dissimilar fibers, such as pulp and textile length fibers,require different flow characteristics as these fibers are projectedinto the expansion and mixing chamber. They can readily be handled,therefore, with the adjustments provided for the sabers.

The nose bar-feed plate assembly must fit tight to the curvature of thelickerins to hold the fibers within the boundary layers of thelickerins. The fibers must not be allowed to expand after they have beencombed out of the feed mats at the nose bars. Expansion of the fiberflow should only be allowed at the junction of the air from the inletair chamber 54 via the venturis formed between the sides of the divider68 and the confronting surfaces of the feed plates 34, 36. This has avery marked effect on the quality of the non-woven web.

In the machine described, the sabers 70, 72 have their axes lying in thesame plane as the axes of the lickerins 46, 48. This allows the centerbaffle 74 to be withdrawn into the air divider chamber, or lowered inthat chamber, to provide the required interface mixing of the two fiberinputs at the final web construction. The common inlet air flow isdivided by the wedge shaped divider, and may also be deflected by theadjustable air vanes above the divider. Thus more or less air may be.

directed toward either side of the inlet chamber, so that more air mayflow to one side or the other as dictated by the type of fibers beingprocessed. This arrangement permits exact control of the fiber and airflow paths, thus allowing, where preferred, maximum interface mixing andgraduated layer control in the final web construction of two dissimilarfibers, such as pulp and textile length fibers, which have differentflow characteristics.

By pivotal adjustment of the vanes and of the vertical position of thedivider plate, substantially complete control over the character of therandom fiber web formed in the machine can be obtained. A web can beformed in which the bottom layer consists substantially of all shortfibers, the upper layer contains substantially all long fibers, and anintermediate layer is formed in which the short and long fibers blend;and the thickness of this intermediate layer can be varied, or reducedsubstantially to zero.

As in U.S. Pat. No 3,512,218, the mixing and expansion chamber isbounded by side walls 110 and 1 12. The side wall 110 may be relativelyfixed, but the side wall 112 is made in two parts hingedly connected toone another. It pivots at one end about the axis of roll 116; and itpivots intermediate its ends on the hinge 1 18. It is adjustable byadjustment of its lower part 120 to control the thickness or weight ofthe web being formed. Adjustment of the lower section 120 may beeffected by adjustment of a screw (not shown), which is manipulated by aknob 124, and which threads into the lower part 122 of the frame of themachine, and is carried by a link 126 that is connected by the plate 128to the lower section 120 of the side wall.

The embodiment of the invention shown in FIG. 2 is similar to that ofFIG. 1, and like parts in this figure are denoted by the same referencenumerals as employed in FIG. 1.

In this embodiment, the air divider 168 extends upwardly to the plenumchamber 154 which receives the air from the duct 50. The central airvane 62 is eliminated; and the adjustable pivotal vanes 58 and 60 arepositioned in the passages formed at opposite sides of the divider 168.Also, the adjustable sabers 70 and 72 here operate as velocity controldevices at the inlet jet point of the input air to the mixing andexpansion chamber 80. Otherwise, the operation is the same as describedwith reference to the first embodiment of the invention.

FIG. 3 of the attached drawings shows fragmentarily a somewhat differentembodiment of the invention. In this figure, parts similar to thosealready described are designated by the same reference numerals asemployed in FIGS. 1 and 2.

Here the divider, which is designated as a whole at 200, has flexibleside walls 202 and 204 which are coupled at their upper ends 205, as bya spring and extend over a roller 206. These side walls are adjustabletoward and away from the lickerins 46, 48 to control the width of thepassages 210 and 212 between the lickerins 46 and 48 and the divider.Adjustment of the side walls 202, 204 is effected by rotation of therollers 214 and 216, respectively, which are mounted eccentrically onshafts 218 and 220, respectively.

A coil spring 222, which is secured at opposite ends in loops 224 and222, respectively, that are welded to the sidewalls 202 and 204,respectively, holds the side walls against the rollers 214, 216. Thespring passes under a roller 228.

The side walls 202 and 204 at their lower ends engage straps 230 and232, respectively, which are secured by plates 234 and 236 and screws238 and 240, respectively, to side plates 242 and 244, respectively,which, in turn, are fastened by screws or rivets 246 and 248,respectively, to the plates 250 and 252, respectively, that serve asguides for a centering member 254, which is adjustable vertically in thedivider. For the purposes of this adjustment, the unit 254 is fastenedto a block 256 which is secured to a screw' shaft 258 that is journaledin a bridge member 260', which is welded at opposite ends to the plates242 and 244. The shaft is journaled in a suitable bushing 262 fastenedon the upper side of the bridge member 260. Adjustment of the shaft maybe effected by gears orchains, which mesh with gears or sprockets 274and 276, that are keyed to the shaft 258. t

In this embodiment, doffing of the fibers from the lickerin is achievedby the doffing plates 247 and 276, respectively, which are fastened toplates 278 and 280, respectively, by screws282 and 284, respectively.Wipers 286 and 288, respectively, are fastened to these plates 278 and280, respectively, by screws 290 and 292, respectively. The wipersengage the rollers 294 and296, respectively, on which the side plates298 and 300, respectively, are mounted, These side plates bound theoutsides of the passages 302 and 305 through which the respective fibersflow to the mixing chamber.

The side wall 298 can be adjusted by manipulating the handle 306. A sea]308, which is fastened to the side plate 298, and which is positioned toengage the upper reach of the condenser screen 82, serves to sealagainst the passage of fibers out of the machine.

Side plate 300 may be made in two parts, as are the side plates 112previously described. The lower section of side plate 300 may be pivotedat 310 on its upper section, and this lower section may be adjusted by alink 126, which is secured to the plate 128 similar to that previouslydescribed. A screw operated by a knob 124 and threading into the framesection 122 of the machine is provided for effecting this adjustment.

Cover plates 314 and 316 are provided adjacent the lickerins 46 and 48,respectively, to prevent the air layer around the lickerins fromcarrying fibers around them.

With the construction shown in FIG. 3, the nose 254 of the centerdivider 200 may be lifted or lowered to allow for intermixing of thefibers at the interface of the two web structures developed at eitherside of the center. Hence, we are able to adjust the amount of gradationbetween the fibers on the lower face to those of the upper face of thenon-woven web formed on the machine. Thus, the machine may be employedto simultaneously process into a single web two different kinds offibers, for instance, polyester fiber on one face and bleached pulpfiber on the other face.

In all embodiments of the invention, the air inlet supply chamber uses acommon inlet, and is principally a closed circuit connected with suctionchamber below the condensing screen. Atmospheric air may bleed into thesystem via ports situated on the suction side of the fans and downstreamfrom the suction chamber. Thus we may allow the fans to work at thedesignated static pressure and flow conditions so as to provide thenecessary positive and negative pressure flow within the machine.

While the invention has been described in connection withseveral'different embodiments thereof, it will be understood that it iscapable of further modification, and th'is application is intended tocover any modifications of the invention that come within its scope orthe limits of the appended claims.

Having'thus'described my invention, what I claim is:

l. A machine for forming random fiber webs comprising i a frame,

two separate, laterally-spaced foraminate condensers rotatably journaledin said frame,

separate conduits for conveying fibers suspended in air to saidcondensers to form fiber mats on the two condensers means'for doffingthe mats from the two condensers,

two rotary lickerins rotatably joumaled in said frame,

means for feeding the mats into the lickerins so that the lickerins intheir rotation comb fibers from the two mats, respectively,

a plenum, k

means for supplying air under pressure into said plenum,

an air balancing chamber,

means for directing an air stream from said plenum into said balancingchamber,

a divider dividing said balancing chamber into two separate passagewaysthrough which the air from said plenum flows past the two lickerins,respectively, to doff, in conjunction with the high speed rotation ofthe lickerins, fibers from the lickerins,

separate means adjacent the lower end of said divider and associatedtherewith for separately adjusting independently of one another thedepths of each of the two passageways, respectively, thereby selectivelyto throttle the flow of air and fibers through said passageways,

a common mixing and expansion chamber disposed beneath said passagewaysin communication therewith and into which the fibers doffed from thelickerins are carried by the two airstreams in the two passageways,

said mixing and expansion chamber being open at its lower end,

a foraminate condenser movable across the open lower end of said mixingand expansion chamber, and

suction means disposed in operative relation to the last-named condenserto cause fibers to be drawn from said mixing and expansion chamber anddeposited on said last-named condenser to form a random fiber webthereon.

2. A machine as claimed in claim 1 wherein said divider is wedge-shapedand has latterally adjustable, downwardly diverging sides which bound,respectively, one side of each of said passageways.

3. A machine as claimed in claim 2, wherein a plate is mounted in saiddivider, and means is provided for moving said plate into and out ofsaid mixing and expansion chamber and to variable depths therein, tocontrol the point where the air streams carrying fibers into said mixingand expansion chamber blend.

4. A machine as claimed in claim 3, wherein vanes are disposed abovesaid divider and are pivotally mounted in said balancing chamber forpivotal adjustment to control the direction and velocity of flow of theair stream in said balancing chamber.

5. A machine as claimed in claim 4, wherein the vanes are disposed insaid passageways.

6. A machine for forming random fiber webs comprising a frame,

two separate, laterally-spaced foraminate condensers rotatably journaledin said frame,

separate conduits for conveying fiber suspended in air to saidcondensers to form fiber mats on the two condensers,

means for doffmg the mats from the two condensers,

two rotary lickerins rotatably journaled in said frame,

means for feeding each of the mats into a different one of saidlickerins so that each lickerin in its rotation combs fibers from one ofthe two mats, respectively,

a first chamber,

means for directing an air stream into said first chamber,

means dividing said chamber into two separate passageways through whichthe air in said chamber flows past the two lickerins, respectively, todoff, in conjunction with the high speed rotation of the lickerins,fibers from the lickerins,

a mixing and expansion chamber disposed beneath said passageways incommunication therewith and into which the fibers doffed from thelickerins are carried by the airstreams,

said mixing and expansion chamber being open at its lower end, aforaminate condenser movable across the open lower end of said mixingand expansion chamber,

suction means disposed in operative relation to the last-named condenserto cause fibers to be drawn from said mixing and expansion chamber anddeposited on said last-named condenser to form a random fiber webthereon,

said dividing means being wedge-shaped and having downwardly divergingside walls which bound, respectively one side of each of saidpassageways, and

means for varying the angular positions of said side walls to vary thedepth of the passageways.

7. A machine as claimed in claim 6, wherein said side walls are movabletoward and away from one another, and the means for varying the angularpositions of said side walls comprise rollers disposed in engagementwith said side walls, each of said rollers being mounted for rotationabout an eccentric axis whereby upon rotation of a roller the positionof the associated side wall is adjusted to vary the depth of theassociated passageway.

8. A machine as claimed in claim 7, wherein the axes about which therollers are eccentrically adjustable lie in the same plane as the axesof the two lickerins.

1. A machine for forming random fiber webs comprising a frame, twoseparate, laterally-spaced foraminate condensers rotatably journaled insaid frame, separate conduits for conveying fibers suspended in air tosaid condensers to form fiber mats on the two condensers means fordoffing the mats from the two condensers, two rotary lickerins rotatablyjournaled in said frame, means for feeding the mats into the lickerinsso that the lickerins in their rotation comb fibers from the two mats,respectively, a plenum, means for supplying air under pressure into saidplenum, an air balancing chamber, means for directing an air stream fromsaid plenum into said balancing chamber, a divider dividing saidbalancing chamber into two separate passageways through which the airfrom said plenum flows past the two lickerins, respectively, to doff, inconjunction with the high speed rotation of the lickerins, fibers fromthe lickerins, separate means adjacent the lower end of said divider andassociated therewith for separately adjusting independently of oneanother the depths of each of the two passageways, respectively, therebyselectively to throttle the flow of air and fibers through saidpassageways, A common mixing and expansion chamber disposed beneath saidpassageways in communication therewith and into which the fibers doffedfrom the lickerins are carried by the two airstreams in the twopassageways, said mixing and expansion chamber being open at its lowerend, a foraminate condenser movable across the open lower end of saidmixing and expansion chamber, and suction means disposed in operativerelation to the last-named condenser to cause fibers to be drawn fromsaid mixing and expansion chamber and deposited on said last-namedcondenser to form a random fiber web thereon.
 2. A machine as claimed inclaim 1 wherein said divider is wedge-shaped and has latterallyadjustable, downwardly diverging sides which bound, respectively, oneside of each of said passageways.
 3. A machine as claimed in claim 2,wherein a plate is mounted in said divider, and means is provided formoving said plate into and out of said mixing and expansion chamber andto variable depths therein, to control the point where the air streamscarrying fibers into said mixing and expansion chamber blend.
 4. Amachine as claimed in claim 3, wherein vanes are disposed above saiddivider and are pivotally mounted in said balancing chamber for pivotaladjustment to control the direction and velocity of flow of the airstream in said balancing chamber.
 5. A machine as claimed in claim 4,wherein the vanes are disposed in said passageways.
 6. A machine forforming random fiber webs comprising a frame, two separate,laterally-spaced foraminate condensers rotatably journaled in saidframe, separate conduits for conveying fibers suspended in air to saidcondensers to form fiber mats on the two condensers, means for doffingthe mats from the two condensers, two rotary lickerins rotatablyjournaled in said frame, means for feeding each of the mats into adifferent one of said lickerins so that each lickerin in its rotationcombs fibers from one of the two mats, respectively, a first chamber,means for directing an air stream into said first chamber, meansdividing said chamber into two separate passageways through which theair in said chamber flows past the two lickerins, respectively, to doff,in conjunction with the high speed rotation of the lickerins, fibersfrom the lickerins, a mixing and expansion chamber disposed beneath saidpassageways in communication therewith and into which the fibers doffedfrom the lickerins are carried by the airstreams, said mixing andexpansion chamber being open at its lower end, a foraminate condensermovable across the open lower end of said mixing and expansion chamber,suction means disposed in operative relation to the last-named condenserto cause fibers to be drawn from said mixing and expansion chamber anddeposited on said last-named condenser to form a random fiber webthereon, said dividing means being wedge-shaped and having downwardlydiverging side walls which bound, respectively one side of each of saidpassageways, and means for varying the angular positions of said sidewalls to vary the depth of the passageways.
 7. A machine as claimed inclaim 6, wherein said side walls are movable toward and away from oneanother, and the means for varying the angular positions of said sidewalls comprise rollers disposed in engagement with said side walls, eachof said rollers being mounted for rotation about an eccentric axiswhereby upon rotation of a roller the position of the associated sidewall is adjusted to vary the depth of the associated passageway.
 8. Amachine as claimed in claim 7, wherein the axes about which the rollersare eccentrically adjustable lie in the same plane as the axes of thetwo lickerins.